You formatted your link wrong. here is the correctly formatted link

The label field is for what we will see. And the URL field is the actual link.

The markdown syntax is [link label](actual link)

Also: You can always paste links without formatting https://lemmy.world/post/342365

I cant check any checkbox in the settings. Toggles, and text input fields do work, though. But im on GrapheneOS and maybe not priority #1